Method and apparatus for automatically processing a workpiece employing calibrated scanning

• US 4,188,544 A
• Filed: 08/22/1977
• Issued: 02/12/1980
• Est. Priority Date: 08/22/1977
• Status: Expired due to Term

• Current Assignee: Applied Scanning Technology
• Original Assignee: Weyerhaeuser Company (Weyerhauser)
• Inventors: Chasson, Leon H.
• Primary Examiner(s): Grimm, Siegfried H.
• Application Number:
  US05/826,554
• Time in Patent Office: 904 Days
• Field of Search: 250/222 R, 250/223 R, 250/224, 250/234-236, 250/548, 250/559, 250/560, 250/561, 250/571, 356/120, 356/156-160, 356/167, 356/168, 356/376, 144/3 R, 144/312, 358/107
• US Class Current: 250/559.06
• CPC Class Codes: B27B 31/06 Adjusting equipment, e.g. using optical projection see also B27L5/022
• CPC Class Codes: G01B 11/2504 Calibration devices

Abstract

A system for efficiently scanning and processing a workpiece, particularly logs or pieces cut from logs, wherein the workpiece is first scanned by projecting at least one plane light source at a first angle and detecting the intersection line of the plane of light and workpiece at a second angle. Signals representing points on the intersection line are corrected to compensate for errors in the scanning apparatus to generate signals representing spatial coordinates of the workpiece at the intersection line. The spatial coordinate representing signals are analyzed to generate processing control signals for controlling devices acting on the workpiece, such as automatic sawing equipment.

Claims

1. A system for processing a workpiece comprising

means having a field of view for scanning said workpiece in said field of view to generate signals related to the spatial coordinates of said workpiece,

means for converting said signals to processing control signals, said converting means including means for modifying said signals to calibrate said scanning means,

said means for modifying including memory means storing calibration information derived by comparing scanning signals of a known three dimensional reference piece located in said field of view with previously stored spatial coordinates of said known reference piece, and

means for processing said workpiece in accordance with said processing control signals.

2. The combination of claim 1 wherein said means for scanning comprises

means for directing a plane of detectable energy at an angle with respect to said workpiece, and

means for detecting, at a different angle, the intersection line of said plane of detectable energy and said workpiece.

3. The combination of claim 2 wherein said means for scanning further comprises

further means for directing a plane of detectable energy at an angle with respect to said workpiece, and

further means for detecting, at a different angle, the intersection line of said plane of detectable energy and said workpiece.

4. The combination of claim 2 wherein said means for scanning further comprises means for transporting said workpiece relative to said means for directing and said means for detecting.

5. The combination of claim 2 wherein said means for detecting generates digital signals representing points of said intersection line.

6. The combination of claim 5 wherein said means for detecting comprises

means for generating analog signals representing the field of view of said workpiece at said different angle, and

means receiving said analog signals for generating digital signals representing points of said intersection line.

7. The combination of claim 6 wherein said calibration information includes a plurality of calibration factors relating, respectively, to zones of said field of view of said workpiece.

8. The combination of claim 2 wherein said calibration information includes a plurality of calibration factors relating, respectively, to zones of said field of view of said workpiece.

9. The combination of claim 2 wherein said means for directing comprises a collimated beam laser source and lens means for diverging said beam into a thin plate.

10. The combination of claim 9 wherein said means for detecting includes a television camera and band pass filter means centered at the frequency of said laser source.

11. The combination of claim 2 wherein said means for detecting includes a television camera.

12. The combination of claim 11 wherein said means for detecting includes means for counting at a first rate from the television horizontal sync pulse to the leading edge of a pulse representing said intersection line and for counting at a second rate from the leading edge of said pulse to the trailing edge of said pulse, whereby the pulse peak representing the position of said intersection line is determined.

13. The combination of claim 1 wherein the system is for processing a log or pieces cut from logs.

14. The combination of claim 13 wherein said means for processing includes means for sawing.

15. The combination of claim 13 wherein the system is a slant edger system.

16. The combination of claim 13 wherein the system is a slant edger system forming a part of a sector wood production system.

17. A method of processing a workpiece comprising

scanning said workpiece in a field of view to generate signals related to the dimensions of said workpiece,

storing calibration information derived by comparing scanning signals of a known three dimensional reference piece located in said field of view with previously stored spatial coordinates of said known reference piece,

modifying said signals with said stored calibration information,

converting said modified signals to processing control signals, and

processing said workpiece in accordance with said processing control signals.

18. A system for scanning a three-dimensional workpiece comprising

means having a field of view for scanning said workpiece in said field of view to generate signals related to the three-dimensional spatial coordinates of said workpiece, and

means for modifying said signals to calibrate said scanning means,

said means for modifying including memory means storing calibration information derived by comparing scanning signals of a known three-dimensional reference piece with previously stored three-dimensional spatial coordinates of said known reference piece.

19. The combination of claim 18 wherein said means for scanning comprises

means for directing a plane of detectable energy at an angle with respect to said workpiece, and

means for detecting, at a different angle, the intersection line of said plane of detectable energy and said workpiece.

20. The combination of claim 19 wherein said means for scanning further comprises

further means for directing a plane of detectable energy at an angle with respect to said workpiece, and

further means for detecting, at a different angle, the intersection line of said plane of detectable energy and said workpiece.

21. The combination of claim 19 wherein said means for scanning further comprises means for transporting said workpiece relative to said means for directing and said means for detecting.

22. The combination of claim 19 wherein said means for detecting generates digital signals representing points of said intersection line.

23. The combination of claim 22 wherein said means for detecting comprises

means for generating analog signals representing the field of view of said workpiece at said different angle, and

means receiving said analog signals for generating digital signals representing points of said intersection line.

24. The combination of claim 23 wherein said calibration information includes a plurality of calibration factors relating, respectively, to zones of said field of view of said workpiece.

25. The combination of claim 18 wherein said calibration information includes a plurality of calibration factors relating, respectively, to zones of said field of view of said workpiece.

26. A method of scanning a workpiece comprising

scanning said workpiece in a field of view to generate signals related to the dimensions of said workpiece,

storing calibration information derived by comparing scanning signals of a known three dimensional reference piece located in said field of view with previously stored spatial coordinates of said known reference piece,

modifying said workpiece signals with said stored calibration information.